<!DOCTYPE html>
<html>
<title>Reference for transition on pseudo-element</title>
<link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#before-after-content">
<style>
div {
  width: 100px;
  height: 100px;
  background: rgb(255, 191, 0);
}
div::before {
  content: "";
  background: rgb(184, 115, 51);
  width: 100px;
  height: 100px;
  transform: ScaleX(0.5);
  display: block;
  will-change: transform;
}
</style>
<div></div>
